21487163 has 4 divisors (see below), whose sum is σ = 21498048. Its totient is φ = 21476280.

The previous prime is 21487153. The next prime is 21487171. The reversal of 21487163 is 36178412.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21487163 - 2¹⁰ = 21486139 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21487153) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1556 + ... + 6737.

It is an arithmetic number, because the mean of its divisors is an integer number (5374512).

Almost surely, 2^21487163 is an apocalyptic number.

21487163 is a deficient number, since it is larger than the sum of its proper divisors (10885).

21487163 is an equidigital number, since it uses as much as digits as its factorization.

21487163 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10884.

The product of its digits is 8064, while the sum is 32.

The square root of 21487163 is about 4635.4247917532. The cubic root of 21487163 is about 278.0095359288.

The spelling of 21487163 in words is "twenty-one million, four hundred eighty-seven thousand, one hundred sixty-three".